In some of the existing reliability tests of high-voltage metal-oxide-semiconductor (HVMOS) devices, a plurality of sample HVMOS devices is formed on a wafer. The sample HVMOS devices may have different structures, for example, with different sizes and dimensions. Time dependent dielectric breakdown (TDDB) tests are performed on the sample devices. Typically, the TDDB tests are performed by stressing the HVMOS devices with currents, and the tests may be performed at elevated temperatures. The tests may be performed until the sample devices fail. Accordingly, the tests are time-consuming. The TDDB test results are then analyzed to determine the reliability of the HVMOS devices.
Due to the long time needed to perform the TDDB tests, the tests are difficult to catch up with the product design cycle time. Furthermore, the existing TDDB tests do not support the establishment of design rules, and designers cannot use the results of the TDDB tests to guide the design process.